Objective: To assess the preventive effect of the antioxidant N-acetylcysteine on postoperative acute renal failure in patients with renal insufficiency undergoing cardiac surgery.
Design: Randomized, placebo-controlled, prospective study.
Setting: University cardiology center.
Patients: Two hundred fifty-four consecutive patients with chronic renal insufficiency (estimated creatinine clearance ≤60 mL/min) undergoing elective cardiac surgery.
Interventions: Patients were randomized to receive N-acetylcysteine (n = 129) or placebo (n = 125). Patients of the N-acetylcysteine group received four boluses of intravenous N-acetylcysteine (1200 mg every 12 hrs, starting immediately before cardiac surgery).
Measurements and Main Results: The incidence of postoperative acute renal failure (>25% increase in serum creatinine from baseline) and the in-hospital clinical course were evaluated. Acute renal failure occurred in 46% of patients and was associated with increased in-hospital mortality (7% vs. 0.7%; p = .024). It occurred in 52% of control patients and 40% of N-acetylcysteine-treated patients (p = .06). In-hospital mortality and need for renal replacement therapy were not affected by N-acetylcysteine, but a lower percentage of N-acetylcysteine-treated patients required mechanical ventilation prolonged for >48 hrs (3% vs. 18%; p < .001) and had an intensive care unit stay >4 days (13% vs. 33%; p < .001).
Conclusions: Intravenous administration of N-acetylcysteine does not clearly prevent postoperative acute renal failure in patients with renal insufficiency undergoing cardiac surgery.